This application addresses broad Challenge Area "Comparative Effectiveness Research" (05) and the specific Challenge Topic "Understanding the Effects of Bariatric Surgery on Type 2 Diabetes and Cardiovascular Risk Factors" (05-DK-102). Bariatric surgery is currently the most effective and durable treatment for extreme obesity. Furthermore, as suggested by several studies and meta-analyses, it is associated with improvements or resolution of several obesity-related comorbidities (particularly type 2 diabetes) in a large majority of individuals. For these and other reasons, there is great enthusiasm among some professional groups to use bariatric surgical interventions to treat type 2 diabetes in individuals with a body mass index (BMI) <35 kg/m2, which is the lowest BMI recommended by the National Institutes of Health and reimbursed by most insurance companies. Despite the potential promise of bariatric surgery as a treatment for type 2 diabetes for these individuals, several unanswered questions remain. First, there have been no randomized controlled trials that compared the efficacy of Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable banding (LAGB), with each other, and with intensive non-surgical weight loss intervention, for ameliorating type 2 diabetes. Second, the mechanisms by which RYGB and LAGB improve gylcemic control are not well understood. Third, in the absence of more definitive understanding of these mechanisms, the level of acceptance of surgical treatment of type 2 diabetes among practitioners (i.e., endocrinologists and primary care physicians), as well as obese diabetics themselves, is unknown. The proposed study is designed to address these questions. In a randomized controlled trial, we propose to study diabetes remission and changes in insulin sensitivity and b-cell function in diabetic individuals with a BMI of 30 to and 40 kg/m2 who are randomly assigned to RYGB, LAGB or intensive non-surgical weight management. We also propose to study attitudes toward and acceptability of these bariatric procedures among endocrinologists and primary care physicians, who are likely to provide referrals for this future group of potential patients. We also will assess the acceptability of bariatric surgery among obese type 2 diabetics themselves. The large weight losses seen with bariatric surgery are often associated with improvements or resolution of several obesity-related comorbidities, including type 2 diabetes. The proposed project is designed to compare improvements in diabetes control in obese diabetic individuals who are assigned by chance to one of three groups: 1) Roux-en-Y gastric bypass;2) laparoscopic adjustable gastric banding;or 3) intensive non-surgical weight management. In addition, the project will study the level of acceptance of surgical treatment of type 2 diabetes among physicians, health care providers, and insurance companies.